A tooth is comprised of an inner dentin layer and an outer hard enamel that is coated with a protective layer called the acquired pellicle. The enamel layer is composed of hydroxyapatite crystals that create a somewhat porous surface. The pellicle or the enamel can become stained or discolored. It is believed that the porous nature of the enamel layer is what allows staining agents and discoloring substances to permeate the enamel and discolor the tooth.
Tooth discoloration has a number of causes. For example, the teeth may become stained by coffee or tea drinking, or by the use of tobacco products, or by drinking water with a high mineral content.
One solution to the staining problem is through tooth bleaching. Some dentifrices, like toothpastes, gels, and powders, contain active oxygen or hydrogen peroxide liberating bleaching agents including peroxides, percarbonates and perborates of the alkali and alkaline earth metals or complex compounds containing hydrogen peroxide.
Dental bleaching can be done either in a dental office or at home. Bleaching in a dental office generally employs compositions activatable with the aid of light sources having the appropriate wavelength outputs in order to speed up the process. Additionally, the bleaching compositions used in a dental office typically contain a higher percentage concentration of bleaching agents than the bleaching compositions found in home applications.
In addition to staining, tooth decay, resulting in cavities or other damages can also result. In the field of tooth restoration and repair, dental cavities are often filled and/or sealed with compounds that are photosensitive, either to visible and/or ultraviolet light. These compounds, commonly known as light-curable compounds, are placed within dental cavity preparations or onto dental surfaces and are cured when exposed to light from a dental curing light device.
Unlike dental curing processes, which are generally relatively fast processes, dental bleaching takes a much longer time, sometimes amounting to more than an hour per office visit. In addition, dental restoration is often an unwelcome experience. Therefore, it is advantageous that a person undergoing the processes, either dental restoration or bleaching, be as comfortable as possible.
The process is generally performed in a dentist's chair. Typically a dentist's chair has a wide range of adjustability such that a patient may be placed in a wide range of positions from a nearly full reclining position to a nearly upright position. In order to effectively accomplish the whitening or restoration process, a light source needs to be aligned with the mouth. The wide range of dentist's chair positions can make this alignment difficult.
Further considerations in the process of dental procedures include the ability to maintain cleanliness of the light source, and particularly of any part that comes into contact with the patient. Further, the process of whitening is preferably optimized, that is, the light source is on as long as necessary to whiten the teeth to the desired degree. Still further, it is preferable that the light source be as efficient as possible. An efficient lamp tends to be cooler and therefore safer than an inefficient lamp. Also, an efficient lamp requires less energy to run than an inefficient lamp.
It remains desirable to have an efficient and comfortable apparatus and method for dental whitening.